The prognosis for primary malignant brain tumors remains poor. In a Phase I trial, one specific type of effector cell, alloreactive cytotoxic T lymphocytes (CTL), have shown promise. Study of glioma cells, damaged by treatment with alloreactive CTL, with other auxillary brain cells such as microglia/macrophages in a reconstituted system may help us to better understand other complex interactions involved in situ. We hypothesize that after co-incubating glioma cells with alloreactive CTL, the resulting damaged (apoptotic/necrotic) gliomas will induce microglia/macrophage phagocytic function. We will also determine the effects of dexamethasone on the phagocytic function of microglia/macrophages. Lastly, we hypothesize that after co-incubating glioma cells with alloreactive CTL, the resulting damaged gliomas will induce microglia/macrophage activation.